New Zealand investors have been told by international fraud investigators to beware of charismatic money-men and unbelievable investment opportunities made over the internet.

Fraud investigators from the United Kingdom, the United States and further abroad have gathered in Auckland this week for the inaugural meeting of the Economic Crime Agency Network to discuss ways to improve co-operation in chasing money across borders.

Acting Serious Fraud Office chief executive Simon McArley, whose agency is hosting the meeting, said this morning that the seminar included discussion on the identification and prosecution of ponzi schemes.

"Over the last 12-18 months we've had seven or so ponzi schemes we've taken to prosecution or have suspicions about," he said.

McArley said the cases of Allan Hubbard's Aorangi Securities, Jacqui and Mike Bradley's B'On scheme and the still-under-investigation Ross Asset Management, were recent local cases where investors lost tens of millions of dollars as funds were recycled without being invested.

Keynote speaker Harry Markopolos, the financial specialist who blew the whistle on the Bernie Madoff US$65 billion (NZ$78b) ponzi scheme, said investors should be wary of confident fund managers promising the earth.

"Look for returns that are too good to be true," he said.

Markopolos said white-collar criminals were better-educated than their blue-collar counterparts.

"They're intelligent people and they've got tried and tested means of drawing people in," he said.

Markopolos said fraudsters who occupied senior positions in business could cause extraordinary damage.

"You can steal a lot more if you're the CEO of the bank than if you try robbing one of its branches," he said.

Commander Stephen Head from the economic crime directorate of the City of London Police said ponzi operators relied on strong interpersonal skills to attract investors and manufacture trust.

"They are compelling characters, they are very charismatic. People are drawn in by the size of their personalities," he said.

"For years we saw 2 per cent of frauds we investigated were enabled over the internet, now it's almost half," he said.

"You shouldn't send large sums overseas without checking them out."

McArley said early detection was key to minimising losses.

"Ponzi operators tend to operate off the radar," McArley said.

"Often regulators don't know they exist until they get complaints about missed payments - by then it's often too late."

Head said fraudsters transferring money across borders made investigations much more difficult. Some jurisdictions were opaque, but better relationships between authorities would make tracking funds easier.